# !/usr/bin/env python
# -*- coding: utf-8 -*-

# 顺序查找
# 时间复杂度：O(n)
# 空间复杂度：O(1)
def order_search(num_arr, num):
    for i in range(0, len(num_arr)):
        if num_arr[i] == num:
            return i
    return None


if __name__ == '__main__':
    arr = [1, 3, 5]
    res = order_search(arr, 7)
    print(res)